The Earth Harp is the largest stringed instrument on the planet. It was developed by William Close in 1999. The body of the instrument rests on the stage and the strings travel out over the audience attaching to the back of the theater, turning the theater / concert hall, architecture and landscape into the instrument. The giant long strings are played with violin rosin covered gloves. The player runs their hands along the strings creating beautiful cello like tones. The reason it is titled the Earth Harp is do to the fact that the first time it was installed, the strings ran from one side of a valley 1000 ft across to the other side, turning the Earth / landscape into a giant harp. The Earth Harp has been installed around the world. The Strings have stretched to the top of the Seattle Space needle, To temples in Vietnam, in the famous Grand Theater of Macau and the Coliseum in Rome. Additionally, it has draped over amazing architecture in Hong Kong, India, and to the Kennedy Center and Lincoln center in the United States.

William studied sculpture and sound design at the Art Institute of Chicago. His unique combination of sculpture, music and installation art blossomed into a new genera of music making designs. His installations and performances have been experienced through out the world. William Close is an installation artist and musician that has developed over 100 new types of musical instruments. Some of Close's other instruments include the Drum Orb, the Percussion Jacket, the Aquatar, and the Wing harp. William Close is also the Founder and Artistic Director of MASS Ensemble. MASS is and acronym for music architecture sound and sculpture. The group works with Close's unique designs to create music based stage shows that push the envelope of the musical experience.

Closes work explores the connection between architecture and music. Inspired by the quote “architecture is frozen music”, Close creates musical installations that use the architecture as part of the instrument. He has developed two Symphonic houses working with architects to build the musical instruments into the architecture.